Black carbon (BC) emissions from ships contribute to human induced climate warming and are linked with human health issues, such as lung cancer, respiratory illness, and cardiopulmonary disease. Unfortunately, published BC emission factors can vary more than ten-fold, leading to uncertainty in estimating shipping’s contribution to BC emissions in the Arctic and globally. To address this uncertainty, the ICCT commissioned researchers from the University of California - Riverside (UCR), Environment and Climate Change Canada (ECCC), National Research Council Canada (NRC) and Eastern Research Group (ERG). The Climate and Clean Air Coalition (CCAC) and the U.S. Department of Transportation Maritime Administration (MARAD) generously provided funding for the study. This study measured marine BC emissions in the lab and onboard two container ships, one with a modern Tier II main engine and another with an older Tier 0 engine outfitted with an exhaust gas cleaning system (EGCS).
The researchers found good agreement among BC emission factors measured with photo-acoustic spectroscopy (PAS), thermal optical analysis (TOA), laser induced incandescence (LII), and light absorption filter smoke number (FSN) methods. Results suggest that BC emission factors are influenced by fuel characteristics, engine type, engine load, and exhaust gas aftertreatment technology. Distillate fuel had the lowest BC emission factor compared to heavy fuel oil (3.2% sulfur) and desulfurized residual fuel (0.0013% sulfur). The modern Tier II engine had much lower BC emissions than the older Tier 0 engine. Black carbon emission factors tended to decrease as main engine load increased in the onboard vessel trials. Lastly, the EGCS reduced BC emissions on the order of 30%.